Bimetallic products and manufacture thereof



'March 5, 1.946. w. KEENE BIMETALLIC PRODUCTS AND MA'UF'ACTURE THEREOFFiled Jan. 22, 1942 5 .flyi

INVENTOR ceding` .om but which 'in the andy .portion thereof beneath thesurface has a carbon con tent well above .08%. Such a steel not onlydesirably inhibits hydrogen absorption at the surf face during picklingbut is readily obtainable at reasonable cost and imparts to thecomponent desirable physical properties which it would not lhave if thecarbon content throughout the component were not substantially greaterthan .08%. While I amnot certain as to the theory of action and make vnorepresentations with respect there-y to, I believe that the fact thatthe outside layer of the rimming or capped steel component is relativelypure iron and low in carbon results in a much slower reaction betweenthe metal and ecid than is` the case when ordinarycarbon steel is used.I believe that as the reaction rate is slower. the amount of hydrogenformed is less and consequently less hydrogen is absorbed.

When the ferrous metal component of a bimetallic billet is made out ofmetal of the character above described and such component is assembledwith one or more other components to form the bimetallic billet and suchbillet is rolled into material in sheet or strip form and such materialemployed for the formation of cups the cups are found to be eminentisatisfactory and the cost of production desirab y low.

Other details, objects and advantages nf the be formed is tohavefacing-components top and bottom. A facing component is shown at inFigure 2 and'in Figure 3 the components 2 and 5 (there being two of thelatter) are shown in 5 assembled relationship but before being fastenedtogether.

The component 2 is of ferrous metal. preferably steel. It may be formedby rolling, forging, milling or otherwise. It may be of any desiredlength.

As above mentioned. it is provided with channels top and bottom forreceiving the facing com ponents. Each such channel Ahas a floor B andopposed side walls 1. The facing components lie against the respectivefloors 8 of the channels,

l5 as shown in Figure 3. The metal of the component 2 at thesurfacesfthereof which form the floors 8 of the channels should have acarbon content not substantially exceeding .08%. The side walls l of thechannels should preferably also zo have a carbon content notsubstantially exceeding .08%, although any bubbles or blisters form-'ing at such side walls during hot rolling can ordinarily be squeezedout so that the gas will escape and not cause defects in the strip. Itis g5 possible for the Ventire component 24 to be made 'y of ferrousmetal having a carbon content not substantially exceeding .08% and forcertain uses such-a component may be entirely satisfactory, al though,as above pointed out. it is likely to be invention will ,become apparentas the followingexpensive to obtain and its physical propertiesdescription of a present preferred embodiment `thereof and a presentpreferred method of praci shown in Figure 1 and two components such asshown in Figure 2 assembled but before the, components are fastenedtogether;

Figure 4 is a view similar to Figure 3 but showing the components of thebillet fastened together:

Figure 5 is a view similar to Figures l to 4. inclusive, of hot rolledstrip made from the billet shown in Figure 4;

Figure 6 is a similar view of cold rolled strip made from the hot rolledstrip shown in Figure 5 and after shearing off the edges; and

Figure '1 is a central cross-sectional view through a bullet jacket cupformed from the cold rolled strip shown in Figure 6; the scale of Figure'7 being greater than that of the other gures. s

Referring now more particularly to the drawing, there is shown in Figure1 the ferrous metal component of a bimet'allic billet, such componentbeing designated by reference numeral 2.

It comprises a body 3 and four flanges eachl designated l. As showninFigure 1, the flanges I are arranged in pairs. two flanges at the topof the component projecting generally upwardly in opposed relationshipat the side edges of the component and two flanges at the bottom of thecomponent projecting generally downwardly in.-

opposed relationship at the side edges ofthe component. 'I'hus channelsare formed at the upper and lower faces of the component 2.- viewingFigure l. for the reception of the facing components, it beingunderstood that the billet ,to

due to its low carbon content may not be as desired. I prefer to employa rimming or capped steel whose carbon content at the surface is notsubstantially greater than .08% but whose carbon asl'content beneath thesurface is substantially greater than .08%. Ihave foundfthat such asteel is ideally. suited to the formation of the ferrous metal componentof a bimetallic billet as herein described. When a rimming or capped 40steel is used the component 2 is preferably formed by rolling and theoutside surface of the component will have a. carbon content notsubstantially exceeding .08%. thisi including the surfaces 6 and thesurfaces 1.

After the component 2 has been formed it is preferably thoroughlypickled to remove dirt. scale and oxides and providerparticularly at thesurfaces B and l, metallically clean faces for reception of the facingcomponents. In many cases it is desirable to carry the pickling stepbeyond the mere cleaning of the component and to severely pickle thecomponent 2 sufficiently to roughen its surfaces. The purpose of this isprimarily to roughen the surfaces 5 against which the facing componentslie to promote a strong union between the component 2 and the facingcomponents 5 and insure against relative slippage therebetween duringthe hot rolling. s v I prefer to employ 'a 5% solution of sulphuric o0acid at a temperature of 160 to 180 F. for the pickling step. Wheny itis desired to roughen the surface of the component 2 such component willbe left in the picklingtank for a time which may approach er possiblyslightly exceed two 05, hours. In such time when a steel of the typeabove mentioned is employed the surfaces Vwill of course be thoroughlycleaned and will also be desirably roughened. When the component 2 issubjected to a' severe pickle such as just mentioned. if the carboncontent of the metal thereof at the surface is substantially greaterthan .08% there will be undesirable hydrogen absorption cr occlusionwhich when the bimetallic billet is formed and rolled willI as abovestated, result in the formation of bubbles and blisters between thelayers of metal. Such bubbles and blisters destroy the bond between thecomponents and render at least portions and possibly all of the carboncontent not substantially exceeding .08% is used for formation of thelcomponent 2 such component can be immersed for two hours in sulphuricacid'at a temperature of- 160 to 180 F.

.without undesirable hydrogen absorption. This is as severe a pickle asis likely to be desired at any time. Y

When the component is removed from the pickling bath it is preferablywashed off'with water and then dipped in sodiumI carbonate which tendsto neutralize any remaining acid. This A may be follo-wed by a soak inhot water which aids in rapid drying of the component.

The components 5 are ordinarily of non-ferrous metal such as copper.brass, gilding metal, cupronickel or other relatively soft corrosionresistant alloy. VFor example, I prefer to use a gilding metal which hasa copper content of in the neighborhood/of 90% and a zinc content of inthe neighborhood of Cubre-nickel having a copper content of in theneighborhood of 80% and a nickel content of in the neighborhood of 20%.vis also entirely satisfactory.

The facing components as well as the component 2 are thoroughlycleanedand thev facing components may likewise be severely pickled to roughenthem. They are assembled as shown in' Figure 3 whereafter the flanges 4are deformed inwardly to firmly hold the components 5 in place and formabimetallic billet ready for rollingas shown in Figure 4. The billet maytake various forms, that shown in Figure 4 being merely an example. Forrolling sheetsa bimetallic sheet bar may be similarly or otherwiseformed. Such billet or bar when hot rolled forms strip or sheets 0 When,for example, a rimming or capped steel whose outer surface has avA',I'he product formed in accordance with my invention is of highqualityand free from bubbles or blisters between the layers of metal and may bemade at a cost comparing favorably with .the

cost of making similar products entirely out vof non-ferrous metal. theferrous metal component of the billet may be andl preferably is employedthe amount of hydrogen absorption if any is negligible from thestandpoint of formation of bubbles and blisters during hot rolling.Baking to remove absorbed v or occluded hydrogen is unnecessary. 'I'heprodu ct, in addition'to being of high and uniform quality, possessesadequate mechanical strength and desirable physical properties.

While I have shown and described a present preferred embodiment of theinvention and a present preferred method of practicing the same it-is tobe distinctly understood that the invention is not limited thereto butmay be otherwise variously embodied and practiced within the scope ofthe. following claims.

I claim:

1. A method of making a bimetallic billet comprising providing acomponent of rimmlng or capped steel having a surface vhaving a carboncontent not substantially exceeding .08%, severely pickling saidcomponentso as to substantially roughen its surface, applying to saidcomponent in its-state immediately following pickling' and in contactwith said surface a component of gilding metal 'and fastening saidcomponents irmly together.

2. A bimetallic billet for rolling comprising a 36 pickled steelcomponent having a surface having i3-hydrogen `and a :second preformedlmetal comas shown in Figure 5 in which the metal of the component 2 isfaced at its central portion with the metal of the components 5. Hereinthe word "billet is used generically to include billets and bars and theword "strip is used generically to i include any metal in strip or sheetform.

During the hot rolling the components or layers of the bimetallicmaterial are disposed in faceto-face contact and have their contactingvfaces united to' each other substantially throughout their area ofcontact. The union is believed to be inthe nature of a mechanical. bondor weld, apparently being accomplished by the combination of heatfandpressure.

The strip is preferably cold rolled and either Before or after the coldrolling' step the edges which consist entirely of the metal`of thecomponent 2 are sheared ofi', forming cold rolled strip 'as shown inFigure 6.l Such strip-is used for ponent lying against said surface,saidcompo-` nents being firmly held together ready for rolling, saidfreedom of said-first mentioned component from absorbed hydrogenproviding for substantial freedom from bubbles and blisters between saidcomponents when the billet is hot rolled.

3. A bimetallic strip comprising a pickled steel component having asurface having a carbon content not substantially .exceeding .08% and inits state immediately following pickling being by reason of theaforementioned carbon content substantially free from absorbed hydrogenand a. second metal component lying against said surface, saidcomponents being welded together substantially throughout their area ofcontact, said l freedom of said iirst mentioned component from absorbedhydrogen providing for substantial freedom from bubbles and blistersbetween said components during rolling of the strip.

4. A bimetallic billet for rolling comprising a component of pickled.rimming or capped steel vhaving a, surface having a carbon content notsubstantially exceeding .08% and in its state immediately followingpickling 4being by reason of the aforementioned carbon contentsubstantially free from absorbed hydrogen and va secondmetal componentlying .against said surface, said components being firmly held togetherready for rolling, said freedom of said first mentioned coinponent fromabsorbed hydrogen providing for substantial freedom from bubbles andblisters between said componentswhen the billet is hot rolled.

lwiirfrrzsz. n. naar.

Although a severe pickle of

